Multibrid GMBH German manufacturer tests its 5-MW wind turbines.

Germany is plunging into deep-water wind farms, now starting construction on a major North Sea grid connection. The 400-MW power line will serve the world’s largest deepwater turbine cluster, potentially the first of many.

Nearly 20 North Sea projects have been approved, totalling over 1,200 turbines of up to 5 MW each. The first step will be this year’s start of installation of the 60-MW Alpha Ventus project.

The farm, 45 km north of Borkum Island, will provide operating data and kick-start the wind program, says Ursula Pral, executive secretary of Germany’s Offshore Wind Forum. After a lot of talk, “nothing [has] really happened.”

But the Germans “are taking significant technical risks,” says David Edge, head of offshore activities at the European Wind Energy Association, Brussels. They “have limited North Sea coast so their projects are much farther offshore in deeper water.”

With rotors nearly 120 m in diameter on 100-m-tall towers rising from water as deep as 40 m, the technology is a big leap from current, shallower-water U.K. developments. Only two deepwater European units exist, under trial at Scotland’s Beatrice oil field, says Edge. “Unproven foundations are the first challenge,” he notes.

Multibrid GMBH Huge rotors are required to wring 5 MW of energy from wind in German tests.

Underscoring Edge’s point, for example, Bard Engineering GmbH., Emden, Germany, plans to mobilize one of the world’s largest piling rigs this summer for a trial 90-m-tall tower near Wilhelmshaven, Germany. The tower, in only 10 m of river water, will sit on 44-m piles.

Preparing for the offshore bonanza, E.ON Netz GmbH., Bayreuth, Germany, has begun installing grid connections. As a grid operator, it became liable for the offshore links in 2006, in a government move to cut operator costs.

E.ON Netz plans two transmission corridors, says spokeswoman Joëlle Bouillon. ABB Group is building the first 130-km offshore link under a $400-million contract won last September. The grid company also plans this year to complete the 70-km line to the 30-m-deep Alphas Ventus site, leased to the DOTI consortium of three power companies.

DOTI last year ordered six 5-MW turbines from Multibrid GmbH., Bremerhaven, for $270 million. Next year, REpower Systems A.G., Hamburg, will install six of its 5-MW machines.

RE Power Europe’s first deepwater wind units are being tested at Scotland’s Beatrice oil field

Prokon Nord Energiesysteme GmbH., Leer, Germany, received a license for the site in 2001, selling it for trials to the trust Stiftung Offshore-Windenergie in 2005. Prokon now hopes to get permission for a second project, the $1.5-billion, 80-turbine Borkum West II farm, in the comingweeks, says team member Freerk Nanninga.

German energy developers pin great hopes on wind, as the government strives to reduce carbon emissions while eliminating nuclear power. Well over 25,000 MW of North Sea wind farms have or await approval. But Pral sees major constraints. “There is a scarcity of wind turbines in the 5-MW class,” she says.

E.ON Netz cites research forecasting 3,100 MW in place by 2011. But “we think it will probably be less,” says Bouillon. For Edge, having maybe 2,000 huge turbines generating 10,000 MW of power by 2020 “feels doable.”